addLoadEvent(preparePlaceholder);
addLoadEvent(prepareGallery);

function addLoadEvent(func) {
	var oldonload = window.onload;
	if (typeof window.onload != 'function') {
		window.onload =func;

} else {
window.onload =function() {
	oldonload();
	func;
	}
}
}

function insertAfter(newElement,targetElement) {
	var parent = targetElement.parentNode;
	if (parent.lastChild == targetElement) {
	parent.appendChild(newElement);
	} else {
	parent.insertBefore(newElement,targetElement.nextSibling);
	}
}

function preparePlaceholder() {
	if (!document.createElement) return false;
	if (!document.createTextNode) return false;
	if (!document.getElementById) return false;
	if (!document.getElementById("imageGallery")) return false;
	var placeholder = document.createElement("img");
	placeholder.setAttribute("id","placeholder");
	placeholder.setAttribute("src","images/placeholder.gif");
	placeholder.setAttribute("alt","bus image gallery");
	var description = document.createElement("p");
	description.setAttribute("id","description");
	var desctext = document.createTextNode("Choose an image");
	description.appemdChild(desctext);
	var gallery = document.getElementById("imageGallery");
	insertAfter(placeholder,gallery);
	insertAfter(description,placeholder);
}

function prepareGallery() {
	if (!document.getElementByTagName) return false;
	if (!document.getElementById) return false;
	if (!document.getElementById("imageGallery")) return false;
	var gallery = document.getElementById("imageGallery");
	var links = gallery.getElementsByTagName("a");
	for ( var i=0; i < links.length; i++) {
		links[i].onclick = function() {
			return showPic(this);
			}
		links[i].onkeypress = links[i].onclick;
	}
}

function showPic(whichpic) {
	if (!document.getElementById("placeholder")) return true;
	var source = whichpic.getAttribute("href");
	var placeholder = document.getElementById("placeholder");
	placeholder.setAttribute("src" ,source);
	if (!document.getElementById("description")) return false;
	if (whichpic.getAttribute("title")) {
		var text = whichpic.getAttribute("title");
	} else {
		var text = "";
	}
	var description = document.getElementById("description");
	if (description.firstChild.nodeType == 3) {
		description.firstChild.nodeValue = text;
	}
	return false;
}

addLoadEvent(preparePlaceholder);
addLoadEvent(prepareGallery);